US2840086A - Hair waving method and neutralizing compositions - Google Patents

Description

United States Patent a Application September 23, 1952 Serial No. 311,162

6 Claims. (Cl. 132-7) No Drawing.

This invention relates to permanent Waving of human hair, and particularly to materials, 'and hair waving methods employing'them, by which waves of improved quality may be obtained safely, conveniently and economically. The'method'is of the cold wave'type, and the materials are well adapted to be sold and used as the so-called home kit, as well as professionally.

The present invention eifectively utilizes sulfite-type materials for cold waving, and a fundamental object of the invention is to overcome those problems which heretofore have been regarded as insuperable to the commercial acceptance of proposals to cold Wave hair by the use of sulfite. Extensive practical experience with the sulfite coldwaves of the present invention and of the invention disclosed in our copending patent application Serial Number 311,161, filed concurrently herewith, has demonstrated that those problems have now been obviated.

This experience has also been adequate to show that the wave of the present invention effects a number of improvements over the only cold waving procedure now in any significant use commerciallythe s'o-called thio wave, using thioglycolate lotions. waves, the materials of the'present invention are substantially non-odorous and they greatly reduce the hazards of irritation. The wave produced by the present invention is less susceptible to subsequent relaxation. The problem of susceptibility of hair to alkali degradation is obviated by the present invention by its retention of the hair in an acid environment as contrasted with exposure to alkali for long periods of time, even a matter of hours in many instances, with the conventional thio wave. The danger of hair breakage is substantially reduced by this invention because although the wave develops with speed comparable to that of mercaptan-type lotions, yet if the exposure of the hair to the lotion is prolonged, the destruction so commonly experienced with mercaptan lotions does not take place.

Prior proposals to cold wave hair using sulfite type materials have been unsuccessful for a number of reasons. Knowledge gained from our present invention demonstrates that one fundamental fault has been in attempting to utilize, for sulfite type materials, the reaction mechanism of the conventional mercaptan or thio cold wave, as that reaction has heen understood. The simple reversibility of the widely used hot sulfite reaction appeared to justify the analogy, but'this, as will be shown, is misleading. v I

Inasmuch as sulfite materials, like mercaptans, areire ducing agents, theaccepted practice of using oxidizing agents to reverse the process and rebuild the hair structure broken down by the mercaptan reducing agents, has prompted the use of oxidizing agents to restore hair reduced with sulfite. However, directly 'co-ntrary to the mercaptan type cold wave, the coldreaction of sulfite uponlhair is not direct reduction off disulfide, and the reaction of oxidizing agentsonIsulfiteqeducedhetir will not rebuild the' original disulfide bonds in the keratin molecule but will irreversibly form sulphone'byproducts characterized by hair that is rubbery and waves that are limp and evanescent.

According to the present invention the acid sulfite relaxed hair keratin has its disulfide bonds rebuilt by treatment with an aqueous solution of hexamethylenetetra mine which operates, it is believed, to reverse the sulfite equilibrium reaction which reduced the hair, by forming" inert reactionv product with the acid sulfite, and also possibly by forming a complex with the cysteine moiety of reduced hair. This reversal of the equilibrium reaction rebuilds the disulfide bonds to their original form in the hair keratin. i

In the discussion that follows, the polypeptide structure of which hair is composed is referred to as keratin and any reference to cystine, cysteine, disulfide bonds, or sulfhydryl groups will pertain to the existence of these v groups in the keratin.

In contrast with thio The following equations illustrate the hair softening and rebuilding reactions:

Reducing step Intact hair Acid (cystine) sulfite Relaxed hair Thiosulfate (cysteine) moletyhoi relaxed air Rebuilding step Relaxed hair Thiosuliate (cysteine) moiety of relaxed hair RSSR represents intact hair in which the cystine linkage between two polypeptide chains is unbroken; the symbol SS- designates a disulfide bond of such a cystine linkage. v

RSH represents relaxed hair, the SH delineating the mercaptan radical in the cysteine moiety which results from the mercaptan reduction of the disulfide linkage of keratin.

Hm is hexamethylenetetramine.

Me is a cation.

H is the acid sulfite anion. I

R--SSO Me is the Me salt of a thiosulfate'derivative of keratin resulting from the action of acid sulfite on the other sulfur of the broken disulfide bond.

MeI-ISO .Hm is an inactive complex formed in the reversal with hexamethylenetetramine.

these lone mercaptan radicals are part of a solid material (the relaxed hair) they have limited mobility and very few of'such lone mercaptan radicals aresufiicientlyjnear to another mercaptan-radical to permit their direct reoxidation to disulfide bonds. The great majorityof these mercaptan radicals will, therefore, react with any applied. oxidizing agent irreversibly to yield sulfone and sulfonate terminal groups. instead of the reenforcing S-S- groups of intact hair.

This invention is predicated on our fundamental discovery that oxidizing agents cannot be utilized to reverse the reaction in the waving of hair at room temperature with acid sulfites.- This finding goes beyond the observation that the introduction of an oxidizing agent to the system described in Equation (1 would oxidize the sulfhydryl groups in the relaxed hair as well as destroy the bisulfite on the left-hand side; of the equation. If this were all, we would expect to achieve only inefficient or partialreversal. InAactual fact we have found that no apparentreversal whatever takesplace when any common oxidizing agent (peroxide, bromate, iodatc, perborate, chlorite, etc.) is directly applied. to bisulfitereduced. hair..- Thecystine .content. of .the. hair. does not significantly. 'A,.load-elongation hysteresis loop made on 'bisulfite-reduced fibers before and after oxidizing'treatment shows no, recoverywhatever. Since the acid sulfite constituent on the left-handiside is unquestionably destroyed whenan oxidizing agent is introduced,

it is most surprising that no detectable reversal. of the reaction can be produced by thismeans.

Equation (2) illustratesthe reaction ofthe hexamethylene tetramine on relaxed hair to cause the equilibrium of Equation (1) to shift to the-left to restore the original disulfide bonds. However, this'reversal regenerates the MeHSO which had beenconsumed in the reducing step and this'in turn reacts with more hexamethylenetetramine to become inactivated as a complex. The hexamethylenetetramine may also form a complex with the cysteine which acts as an intermediate in the ultimate reversal. Theneutralizing reaction including'formation of any complex intermediates takes place rapidly upon the simple addition of aqueous hexamethylenetetramine to the relaxed hair.

, This hexarnethylenetetramine neutralization reaction is an equilibrium reaction so that although most of the reduced disulfide bonds are rebuilt by hexamethylene tetramine, some cannot be rebuilt in its presence.' Accordingly, while not essential, it is highly desirable for optimum effectiveness to complete'the destruction of the acid sulfite-which is present at equilibrium. For this purpose an oxidizing agent, properly selected and properly employed, is effective. We :have found that if a slowacting loxidizing agent, such asa" soluble bromate salt, is employed? 'the equilibrium bisulfite is effectively destroyed, and yet the oxidizing action is so slow in comparison with the rapid action of the"hexan1eth'ylenetetramine that the slow acting oxidizing agent may be mixed with the hexainethylenetet'ramine without dangenofoxidation of the sulfhydryl group shown on the right-hand side of Equation (1). However, if a fast actingbxidiz'ing agent, such as peroxide, is employed, having aspeed' of reaction comparable to .or greater than thato'f the hexamethylenetetr'am'ine, the two materials must be usedin sequence to assure that the hexamethylenetetramine completes its reversal before the sulfhydryl group is oxidized to a non-bridging sidechain. J

The hexamethylenetetraminemay form-a complex with the cysteine moietyof reduced hair which tends to pro tect this readilyvoxidizable. substance against premature oxidation. This appears to be the most probable reason why hexamethylenetetramine is effective to reverse the reaction'even in the presence of a slow-acting oxidizing agent.

Proceeding accordingto the present invention, the hair is treated with an acid sulfiteibisulfite) relaxing solution which may be varied both as to its pH value and its normality. depending upon a number of factors. The

ultimate objective is a lotioncontaining an adequate concentration of acid sulfite ions in solution to effect the relaxation in a reasonably short time atroom temperature, and that concentration will vary both with pH and normality. Solutions within a preferred pH range of 6,0 to 6.6 and a preferred strength ofl to 2.5 N will relax normal hair adequately in a preferred time range of ten to seventy-five minutes. Within these ranges, the lower the pH and the higher the normality the higher will be the acid sulfite ion concentration and the shorter the relaxing time required.- A pH as low as 5.5 may be employed but the solution should not have a lower pH value than 5.5 as it would then tend to evolve intolerable amounts of S0 a gas which has a degrading and bleaching effect on the hair and an objectionable odor. A pH value as high as 7.5 is the practical upper limit. If the total titer (sulfite plus bisulfite) exceeds 3.0,N a pH as high as 8 could be used but only under conditions seldom resorted to in' practice, such as dipping the hair in the lotion; With the lowerrange of pH values specified above the concentration of the acid sulfite may be as low as 0.5 ,N.

These ranges of values afford the wide flexibility of treatment necessary to accommodate our invention to the specific requirements of given conditions of use. Thus non-professional home use can involve much longer processing times than could be tolerated economically by the professional beauty operator and time ranges of relaxing treatment from about five minutes to about two hours or even more are readily obtainable within the scope of the present invention.

The hair may be first wound upon rods and then wetted with acidsulfite to relax it, or it-. may be first wetted with acid sulfite and then wound, either sequence being' completed prior.- to" setting by neutralizing. In any event the hairis lefton the rods. in contact with the acid sulfite for-a suitable period of time'b efore neutralization. .1 3

After relaxation with acid sulfite of controlled pH, the hair, while stilliwo'und on rods, is treated with an aqueous solution of hexamethylenetetramine to set the hair by rebuildingv the disulfide. bonds.which.,have been broken by the acid sulfite.-

The hexam'ethylenetetramine is generally applied to the hair as an aqueous solution having a pH range of about 4 to 6.5, preferably 4.5 to 5.5. Theactivity of the hexamethylenetetramine may be varied within the pH. range given, the lower pH tending to speed up and the higher pH tending to retard its rapid acting'etfect to -r'eversc the reaction. j

Where the hexarnethylenetetramine is used in solution with a slow-acting oxidizing agent, the agent is; preferably a bromate of an alkali metal, such as sodium, potassium, or lithium, but the corresponding chlorates may be substituted for bromates with the obvious disadvantages of thehazards involved in their handling. Where hexamethylenetetramine is first applied independently of an oxidizing agent, an oxidizing agent may be subsequently applied. Such independently applied oxidizing agent may be of any character, slow or fast acting as desired. For this purpose, any known oxidizing agents may be used in any quantity sufficient to oxidize and destroy the bisulfite not complexed with the hexamethylenetetramine. It is not absolutely necessary to use an oxidation agent at all, either in combination with the hexamethylenetetramine or following the hexamethylenetetramine, asthe reversal in any event issu'bstantially completed without it. The use of an oxidizing agent is in the nature of an optional but preferred after-treatment to destroy-any residual bisulfite present, such residues having obviously a hair softening effect in .acid'environment. This afterrtrea'tmentcharacter of the oxidation is not changed by thefactthat by the present invention we have been able to apply the. hexamethylenetetramineand a slow oxidizing agent in the same solution. If no oxidizing agent is used, copious rinsing with water to remove residual bisulfite and bisulfite-hexamethylenetetramine complexes -is desirable. The reversal and rebuilding is completed afterexpQSLire to hexamethvlenetetrarnine for a period of about 8 utes or longersuch as up to about 30 minutes, generally depending on the efiiciency of the penetration of the wound tress by the hexamethylenetetramine. The oxidation of bisulfite and its complexes, if by a separate solution may be performed after the hair has been unwound, because the wave has been substantially set as soon as adequately penetrated by the hexamethylenetetramine solution. e

Other after-treatments are sometimes desirable. When the hair is rebuilt by an acid hexamethylenetetramine solution containing a slow oxidizing agent, the hair will, of course, remain acid in the pH range above stated, so that after processing, the hair need merely be unwound from the curling rods and rinsed with water, or, if desired, with any conventional after treatment rinse having no chemical action. Where the hair is treated first with hexamethylenetetramine alone, the subsequently applied oxidizing agent is also preferably acid but may be alkaline, such as an alkali metal bromate in a pH range from 8 to 1 0, in which event a final acid rinse may desirably be employed to restore the hair to its natural acid pH. All such aftertreatments, including any oxidizing agent, may be applied to either wound or unwound tresses.

Acid sulfites of the alkali metals, ammonia or organic amines are effective for relaxing the hair. Thus, useful examples include sodium, potassium or ammonium acid sulfite, simple mono, di-, or tri-alkyl amines such as the methyl, ethyl, propyl or butyl amines, alkanol amines such as diethanol amine, cyclic amines, such as morpholine, piperidine, and piperazine, as well as other basicacid sulfite forming organic substances such as guanidine and formamidine.

Acid sulfites are readily obtainable in a pH range below 5.5 by passing, as by bubbling, S gas through a relatively concentrated solution of a water soluble alkali or alkaline salt having a cation corresponding to the desired cation of the acid sulfite. then be diluted with to 40% of alcohol which brings the apparent pH int-o the preferred range of 6.0 to 6.6. This dilution of the concentrate with 5 to 40% alcohol also may be such as to bring the concentration of the sulfite to the range of 0.5 to 3.0 normal, or the preferred range of 1 to 2.5 normal.

Commercial sulfite solutions thus produced are usually made up from ordinary natural commercial waters, such as tap or spring water,which commonly contain trace quantities of the multi-valent ions of iron, cobalt, copper or manganese. In the presence of oxygen, such ions in trace quantities tend to accelerate oxidation of sulfite in storage so as rapidly to destroy the sulfite in partially filled bottles after they have been opened for use. For this reason the acid sulfite is preferably used in combination with a metal sequestering agent. Such a metal sequestering agent is of the nature of an ammonium or alkali metal salt of a polybasic acid compound. Such polybasic acid compound may be one of the soluble salts of the simple fruit acids such as citric, or tartaric acid or homologues thereof, or salts of succinic, gluconic, glutaric, maleic, or oxalic acid, but preferably are amino derivatives of polycarboxylic acids having the structure R'N(RCOOl\ le) wherein Me is a soluble cation, generally ammonium or any alkali metal such as sodium or potassium; R is a simple lower alkylene such as methylene, ethylene, propylene, etc.; and R is hydrogen, lower alkyl or amino lower alkylene, of Which the alkyl or alkylene has 1 to 3 carbon atoms and the amino group of which may 'be further substituted with metallic acyl groups of this formula. Thus, such compounds as trisodium triacetic acid amine, the tetra sodium salt of tetra acetic acid ethylene diamine, and higher polyamines are useful examples. Compounds of this character are known commercially as Nullapons, Versenes and Sequestrenes. The metal ion sequestering agent is generally used in minor quantities corresponding generally to the quantity of metallic ion to be sequestered and The concentrated solution may will approximately range from .001 to 0.5% of the solution. 1

' The hexamethylenetetramine solution is a simple solution in water. The upper quantity limit of the hexamethylenetetramine is not critical. For the purposes of practical economy it is usually less than 5 molar and is usually made up in concentrations of .05 to 3.5 molar as indicated above preferably in the rangeof .15 to 1.0 M and in a pH range of 4.5 to 5.5. When an oxidixing agent is used, it may be made up with the hexamethylenetetramine in the same water solution if a slow-acting oxidizing agent such as an alkali bromate salt is selected. Such oxidizing salt is usually used in proportion of /2 to 4%. Alternatively, any oxidizing salt such as alkal metal bromate, iodate, chlorate, hypochlorite, perborate or acids such as perboric acid monohydrate, or ordinary hydrogen peroxide, may be used separately and subsequent to the hexamethylen-etetramine treatment. The hexamethylenetetramine solution alone or combined with a slow-acting oxidizing agent, or the solution of oxidizing agent to be used subsequently, may further contain a monobasic sodium phosphate as a bufiering agent, or other acidic buffering salts may be used.

Various common additives useful in hair waving lotions further may be included in either or both the acid sulfite keratin relaxing solution or the hexamethylenetetramine solution. For example, such materials as wetting agents may be used, preferably of a non-ionic type such as the alkyl phenoxy polyethoxy or other polyalkylene oxide derivatives, but anionic and cationic types may be used alternatively if desired, the wetting agent being present in minor quantities ranging from about 0.1 to about 3%. The lotions may further contain opacifying agents, such as oils or insoluble resinous materials such as polymerized methyl inethacrylate together with suitable dispersing or emulsifying agents, to render the solutions opaque, and the solutions may also contain coloring agents, perfumes, etc.- to make the product attractive. These additives, opacifiers, perfumes and colorings are usually used in such minor quantities as from about 0.001 to about 1%.

The chemicals employed in accordance with the present invention are harmless when used in the prescribed manner and they are superior in the wave they produce. A minimum of control is required so that they are excellently adapted for home or nonprofessional use. For this purpose, the chemical solutions, i. e., the hair relaxing lotion and the setting lotion, the two lotions to be applied in sequence to the hair and cooperatively effective for purposes of first relaxing the hair so that it will readily take the curl, and then restoring the curled hair to its original chemical structure so that the wave becomes permanent, may be made up in a home kit.

Some of the compositions may be packaged as dry powder for ultimate addition to a controlled quantity of water just prior to use. It is possible also to furnish some of the kit components as solutions and others as dry powders, depending somewhat upon advantages to be gained in greater storage stability of one form as contrasted with the other, or reduced shipping costs. Thus, both hexamethylenetetramine crystals and bromate salts are sometimes preferably packaged as dry powders with bulfers, etc. to produce the desired acidity when dissolved in water for use. When the slow acting oxidizing agent and hexamethylenetetramine are to be combined in a single solution, either may be packaged dry with the controlling acid buffer distributed in either for optimum stability to give the desired acidity when combined.

The following examples illustrate the practice of this invention Example I.Preparation of keratin relaxing lotiori Sulfur dioxide gas is bubbled at room temperature into a 30% solution in water, of guanidine carbonate to form an 'acid solution of guanidine' blsulfite having a pH of aboutS .8. The solution is filtered,if'necessary,' torernove suspended impurities. The solution is then diluted to approximately double its volume with water, after which 10% N-propyl alcohol is added. This quantity of alcohol will raise the apparent pH of the solution to approximately 6.1. To this solution is added 1% of a metal sequestering agent consisting of sodium 'tri-acetic acid amine. Thereafter, a wetting agent," Triton X-100, an alkyl phenoxy polyethoxy ethanol, is added in quantity of A concentrated suspension of methyl methacrylate polymer, suspended in water, is added sufficient in quantity to cream and body the lotion, about 0.5%. Minor quantities of perfume and color, sufiicient to render the product attractive, are further added.

Example II Ammonium acid sulfite is dissolved in water or may be formed in an aqueuos solution from ammonium carbonate and sulfur dioxide in a manner similar to that described in Example I, and diluted with ethyl alcohol to form a 15% alcoholic solution of the ammonium acid sulfite contained therein in concentration of 1 normal. To this is added .25% of a wetting agent consisting of Triton X-100, 5% of a methyl methacrylate polymer dispersion in water to imparttothe solut ion a creamy appearance and also sufficient perfume and dye to render the product attractive. Additionally, if the solution is made up from tap water, 1% of sodium triacetic acid amine will be added as a 'sequestrant. In this example, the final pH of the solution will be approximately 6.2.

Example III Guanidine acid sulfite formed as described in Example I and containing this acid sulfite in concentration of 2.5 normal and having an isopropyl alcohol content of 30% with further quantity of A% of Triton X-100, is adjusted to pH 7.3 with guanidine carbonates.

Example IV Guanidine acid sulfite prepared as described in Example I, but having a pH of 6.0 and containing 40% of alcohol, the total acid sulfite being adjusted to .25 N, is made up with additional quantities of a non-ionic wetting agent, a creaming agent, and minor quantities of perfume and color, as described in Example I, to form an effective softening agent for relaxing the hair.

Other examples follow:

v Example V Guanidine carbonate; 27lbs. Nullapon Bnm; 1.065 lbs. Sulfur dioxi de 14 lbs. (approx) Isoproply alcohol (91% 2 gals., 91 fi. oz. Alkyl phenol 'polyethoxy ethanol 1 lb. Perfume .i. -l a..;;;.. 0.12 lb. Water 14 gals, 113 fl. oz. Adjust with S or giianidine carbonate to pH 6.6. 7

Example VI Ammonium carbonate (monohydrate) 16.4 lbs. Versene -'0.66 lb. Sulfur dioxide 14 lbs. (approx) Isopropyl alcohol (91%) 2 gals, 91 fl. oz. Alkyl phenol polyethoxy ethanol 1lb. Perfume 0.18 lb. I Water l4 gals, 1 13 fl. oz.

TExample VIIQ-Nutializer solution a 35 grams of hexamethylenetetramine are dissolved in water to form a .25 molar solution. The pH of the solution, at first approximately neutral, isacidified by trace quantities of acetic acid or monoba'sic sodium acid phosphate added to adjustjthepH toapproximately 5.5.. The solution is then ready for use' as a neutralizing solution i 8 and may be used directly alone, or its application may be followed by treating the hair with an oxidizingagent, as s'et'forthin Example .VIII or IX. 7 2 Example VilI.--Oxidizing solution :A 16% by weight solution of sodium bromate is made up in water containing additionally [7% of a buffer consisting of trisodium phosphate dodecahydrate and 7.7% of monosodium dihydrogen phosphate monohydrate, 3% of anytypical wetting agent in solution, 2% of an opacifier, i. e.', a concentrated suspension in water of polymethyl methacrylate, perfume 0.2%, and water approximately 68.4%. The pH of the solution is approximately 4.8. This solution is normally diluted four times with water'prior to use and is of a suitable concentration for supply with a home kit adapted to be further diluted by the user.

' Example IX Example X.--Combined hexamethylenetetramineoxidizer solution 14.0 grams of hexamethylenetetramine is dissolved in one quart of water, and the pH of the solution is adjusted to 5.5 by addition of a small quantity of monosodium acid phosphate. A package is made up consisting of a powdered mixture of 16.0 grams of sodium bromate and 15 grams of monosodium phosphate, the total contents of the package being dissolved in the quart of hexamethylenetetramine just prior to use as a mu tralizer. V

The hexamethylenetetramine solution may further contain a nonionic, cationic or anionic wetting agent such as Triton X-100, Tergitol or other well known wetting agents, of which the alkyl phenoxy polyalkylene oxide alkanols are typical for the non-ionic type, quaternary ammonium chlorides such as benzyl higher alkyl dimethyl ammonium chloride known as Zephiran is typical of the cationic type, and sodium lauryl sulfate or a mixture of alkali metal sulfated alcohols predominating in sodium lauryl sulfate are typical of the anionic type, of which the following is an example:

Example XI 30 grams of hexamethylenetetramine and 15 grams of succinic acid are dissolved in one quart of water. There is further added .1% by weight of Triton X-lOO, 2% by volume of a 20% weight suspension of polymethyl methacrylate in water and traces, q. s. to make the product attractive, of a coloring agent and a perfume.

Example XlI.-Typical hair waving procedure with the chemicals hereof The solution of Example I is combed into dry hair, or hair which has been previously dampened, as by preliminary shampooing and removing of most of the free moisture, to thoroughly distribute the waving lotion on the hair. The wet hair is then wound upon conventional curling rods, and the hair allowed to process in the curled form for approximately 30 minutes. Thereafter, the softened hair on the curling rods is treated by moistening with the solution of Example VII by thoroughly saturating the wound hair therewith and allowing to stand for approximately 15 minutes. As indicated above, the setting of the curl is largely a mater of obtaining thorough penetration and, depending upon the type of rod, the time may vary for a greater .or lesser period. By this treatment the hair has become permanently set and may be unwound from the rods. The hair may be washed to remove the chemicals or may be treated with an oxidizing agent as set forth in Example VIII or IX to destroy residualsulfite.

9 Example XIII.-Setting procedure After the hair has been relaxed for a sufiicient period, as set forth in Example XII, by processing with acid sulfite of solutions prepared as set forth in any of Examples I through VI, it may be set by a combined solution of hexamethylenetetramine with an oxidizing agent. Thus, the hair may be wet in a manner to penetrate thoroughly the tress with a solution as set forth in Example X. After standing for at least eight minutes, and preferably about 15 minutes to be certain that the neutralizing solution thoroughly penetrates the Wound tress, it may be unwound from the curling rod. The hair has been set with the hexamethylenetetramine and the residual sulfite has been removed by oxidation. Hence, no washing of the hair is necessary, although the hair may be washed, if desired, to remove residual salts.

Many other useful examples will occur to the man skilled in the art once the'principle of our invention is understood. Although the theoretical explanation of the mode of operation of various hair waving treatments given here is based on exhaustive research and is believed to be sound, our'invention is, of course, not to be circumscribed by any such statements of theory.

We claim:

1. A method of cold waving hair on the human head comprising softening the keratin of the hair at room temperature by applying thereto about 0.5 to about 3.0 N acid sulfite solution having a pH range from about 5.5 to about 7.5, and then setting the softened hair while deformed upon curling rods by applying thereto an aqueous acidic solution of hexamethylenetetramine.

2. A method of cold waving air on the human head comprising wetting the hair on the human head with about 0.5 to about 3.0 N acid sulfite solution having a pH range from about 5.5 to about 7.5 to soften the same at room temperature, and then setting the hair while deformed upon curling rods with a neutralizing solution comprising an aqueous acidic solution of hexamethylenetetramine and a slow acting oxidizing agent selected from the group consisting of alkali metal bromate and alkali metal chlorate.

3. A method of cold waving hair on the human head comprising wetting the hair on the human head with about 0.5 to about 3.0 N acid sulfite solution having a pH in the range of about 5.5 to about 7.5 to soften the same at room temperature, and then neutralizing the 10 softened hair while deformed upon curling rods, first with an aqueous solution of hexamethylenetetramine, and then with an aqueous solution of an oxidizing agent.

4. A method of cold waving hair on the human head comprising wetting the hair on the human head with an aqueous alcoholic solution of about 0.5 to about 3.0 N acid sulfite salt selected from the group consisting of alkali metal, ammonium, organic amino and organic amido acid sulfites in the pH range of 6.0 to 6.6 to soften the same at room temperature, and then neutralizing the softened hair while deformed upon curling rods with an aqueous acidic solution of hexamethylenetetramine and a slow acting oxidizing agent selected from the group consisting of alkali metal bromate and alkali metal chlorate; said solution being buffered in the pH range of about 4 to 6.5.

5. A neutralizing solution for the setting of hair on the human head which has been softened with an acid sulfite in the waving thereof comprising about a 0.15 to 3.5 molar aqueous solution in the pH range of about 4 to 6.5 of hexamethylenetetramine and a slow acting oxidizing agent selected from the group consisting of alkali metal bromate, and alkali metal chlorate.

6. A dry composition adapted in aqueous solution for setting of hair on the human head which has been softened with an acid sulphite in the cold waving thereof, comprising a mixture of hexamethylenetetramine, a slow acting oxidizing agent selected from the group consisting of alkali metal bromate and alkali metal chlorate, and a buflering agent adapted to maintain said salt mixture in aqueous solution at a pH in the range of about 4 to 6.5

References Cited in the file of this patent UNITED STATES PATENTS 1,008,249 Elsaesser Nov. 7, 1911 2,351,718 Speakman June 20, 1944 2,400,377 Speakman May 14, 1946 2,437,965 Michaels Mar. 16, 1948 2,508,713 Harris May 23, 1950 FOREIGN PATENTS 494,927 Great Britain Nov. 3, 1938 697,634 Germany Oct. 18, 1940 552,285 Great Britain Mar. 31, 1943 534,838 Germany Sept. 25, 1931 928,871 France Dec. 10, 1947

Claims (1)

1. A METHOD OF COLD WAVING HAIR ON THE HUMAN HEAD COMPRISING SOFTENING THE KERATIN OF THE HAIR AT ROOM TEMPERATURE BY APPLYING THERETO ABOUT 0.5 TO ABOUT 3.0 N ACID SULFITE SOLUTION HAVING A PH RANGE FROM ABOUT 5.5 TO ABOUT 7.5, AND THEN SETTING THE SOFTENED HAIR WHILE DEFORMED UPON CURLING RODS BY APPLYING THERETO AN AQUEOUS ACIDIC SOLUTION OF HEXAMETHYLENETETRAMINE.